1. Field of the Invention
The present invention relates to a condenser for condensing a low temperature fluid through a heat transfer from a high temperature fluid to the low temperature fluid, and especially to a condenser having high condensation efficiency.
2. Description of the Related Art
In general, a condenser is used in a plant of electric generation by temperature difference, steam power, chemistry, food engineering and the like, a refrigerator and a heat pump. Such a condenser can make heat exchange between high temperature fluid and low temperature fluid for the purposes of making change of phase of the high temperature fluid from a gaseous phase to a liquid phase. The conventional condenser maybe classified into a shell and tube evaporator, a plate type evaporator, a spiral type evaporator and the like. The plate type condenser is generally used as a condenser for condensing the high temperature fluid by absorbing heat of the high temperature fluid with the use of the low temperature fluid for example in a plant of electric generation by temperature difference. An example of the conventional condenser is shown in FIGS. 6 and 7. FIG. 6 is an exploded perspective view illustrating essential components of the conventional condenser. FIG. 7 is a schematic descriptive view of the conventional condenser in an assembled condition.
The conventional condenser 100 as shown in FIGS. 6 and 7 is provided with pairs of heat exchange plates 101, 102. In each pair, the heat exchange plate 101 is placed on the other heat exchange plate 102. Upper and lower guide rods 105, 106 held between a stationary frame 103 and a support rod 104 support the pairs of these heat exchange plates 101, 102. The pairs of the heat exchange plates 101, 102 are firmly held between the stationary frame 103 and a movable frame 107 that is mounted on the guide rods 105, 106. Two heat exchange passages A, B are formed on the opposite surfaces of each of the heat exchange plates 101, 102. A high temperature fluid 108 flows in the heat exchange passage A and a low temperature fluid 109 flows in the other heat exchange passage B so as to make heat exchange.
The above-mentioned heat exchange plates 101, 102 having a prescribed shape and a surface condition can be obtained by press-forming a plate-shaped material. Openings "a", "b", "c" and "d" through which the high temperature fluid 108 or the low temperature fluid 109 can pass, are formed at four corners of each of the heat exchange plates 101, 102. Packing members 111, 112 are placed on the surfaces of the heat exchange plates 101, 102, respectively, so as to prevent the heat exchanger fluid 108 and the working fluid 109 from flowing in a mixing condition. The heat exchange plates 101, 102 have the same shape, but the heat exchange plates 102 is placed upside down relative to the normal placement of the heat exchange plate 101.
The heat exchange plates 101, 102 serving as the heat transferring face has a pattern of irregularity (not shown) formed thereon in order to increase the heat transferring area and facilitate the heat transfer from the high temperature fluid 108 to the heat transferring face as well as the heat transfer from the heat transferring face to the low temperature fluid 109.
There is known the other plate type condenser in which, as a part of a pattern of irregularity of a heat transferring face, a plurality of vertical grooves 202 having appropriate pitch and depth are formed on the high temperature fluid side of a heat transferring face 201 as shown in FIG. 8, or a plurality of condensate discharging grooves 302 are formed on a heat transferring face 301 in the oblique direction to the flowing direction of the high temperature fluid as shown in FIG. 9.
When the above-mentioned vertical grooves 202 are formed, condensate of the high temperature fluid, which condenses on the heat transferring face 201, is collected in the trough portions of the vertical grooves through the surface tension of the condensate so that the condensate collected in the trough portion can flow down by its own weight. Accordingly, it is possible to restrain formation of a condensate layer covering the heat transferring face 201 so as to improve the heat transfer efficiency. On the other hand, the above-mentioned condensate discharging grooves 302 receive condensate halfway, which is generated on the heat transferring face 301 to flow down, so that the condensate can be discharged smoothly along the condensate discharging grooves 302. Accordingly, it is possible to prevent the condensate from staying on the heat transferring face 301 so as to improve the contact efficiency of the heat transferring face 301 and the gaseous high temperature fluid.
In the conventional condenser having the above-described structure, although the pattern of irregularity, which facilitates the discharge of the condensate so that the maximum coefficient of heat transfer in the high temperature fluid can be provided, is formed on the high temperature fluid side of the heat transferring face, the low temperature fluid side of the heat transferring face merely has a pattern of irregularity that has an inverse relationship in concavo-convexities to the above-mentioned pattern of irregularity, which is formed on the high temperature fluid side. More specifically, the coefficient of heat transfer relative to the low temperature fluid is not considered in the pattern of irregularity of the low temperature fluid side of the heat transferring face. Accordingly, the heat transfer efficiency is not sufficiently optimized in the heat transfer from the heat transferring face to the low temperature fluid, thus causing energy loss.